1. Field of the Invention
This invention generally relates to apparatus for producing electrical energy and has particular reference to a compact mechanically-powered electric generator suitable for use as an integral power source in a camera or other device.
2. Description of the Prior Art
Photographic cameras having mechanically actuated and driven generators that produce an electric current which fires a photoflash lamp or energizes other devices in the camera are well known in the art. A camera having such an electric generator wherein a voltage pulse is produced by a flat coil of wire that is attached to the camera shutter and propelled into the gap of a permanent magnet when the shutter is tripped is disclosed and claimed in U.S. Pat. No. 3,709,118 issued Jan. 9, 1973 to the present applicants. The "built-in" electric generator replaces the batteries normally employed in the camera and thus eliminates the aggravating problem of lamp misfires due to weak or dead batteries and high-resistance contacts with the terminals of the batteries.
A camera having a flap-type shutter with a permanent magnet that enters a stationary wire coil when the shutter is actuated and thus generates a voltage which "fires" a thyratron tube in an external electrical circuit that flashes a gaseous discharge lamp is described in U.S. Pat. No. 2,538,577 issued Jan. 16, 1951 To C. W. McCarty. A camera having a magnetic circuit with an oscillating core element which generates a voltage and fires a photoflash lamp when the shutter is actuated is disclosed in U.S. Pat. No. 3,480,808 issued Nov. 25, 1969 to H. F. Reith. A camera with an electric generator wherein the voltage is produced by a magnet which is rotated when the shutter is tripped is disclosed in Japanese Pat. No. 39-22075 published Oct. 7, 1964.
Various other types of electric generators per se that produce electrical energy in response to changes in the flux density or flux distribution in a magnetic circuit as disclosed in U.S. Pat. Nos. 2,426,322; 2,784,327; 2,904,707; 3,065,366; and 3,500,086.
Camera flashguns having integral electric generators comprising a permanent magnet and a pivoted armature that is actuated manually by a shutter-release cable or by a leaf spring are disclosed in U.S. Pat. Nos. re 22,433; 2,448,897 and 2,490,225.
While the prior art cameras with integral electric generators greatly simplified the picture-taking operation by eliminating the batteries and the various problems they created, further improvements which will reduce the cost and size of the generators would be highly desirable, particularly in view of the continuing trend to make cameras as compact and reliable as possible. It would also be desirable to increase the electrical out-put of such mechanically-powered generators without increasing their physical size and, preferably, to accomplish this with a generator that is more compact and can be easily and automatically cocked.